Is gender a social construct?

There are biochemical differences in the brains of men and women determining their behaviour

Question: Is gender a social construct?
Position‹2 of 3›: Gender is not a social construct
Argument‹2 of 2: There are biochemical differences in the brains of men and women determining their behaviour

Due to hormonal differences, the development of the human brain varies in males and females, determining their gender.

The argument

Sexual differentiation of genitalia takes place within the first two months of a pregnancy. The sexual differentiation in the brain begins to only take place in the second trimester. Testosterone determines whether the brain develops as a male or female. These differences determine sexual orientation and gender identity. Hypothalamic differences show the variation. For example, the preoptic area which regulates mating behaviour is 2.2 times larger in a male with twice as many cells. This depends on the number of androgens. These differences become apparent at the age of 4. After the age of 4, the number of cells in this nucleus decrease for females. These differences impact several functionalities and the sexual preferences of the individual.

Premises

[P1]Testosterone drives the brain to develop as male or female during the second trimester, distinct from the earlier differentiation of genitalia. [P2] Hypothalamic structures differ measurably by sex — the mating-regulating preoptic area is 2.2 times larger in males, depending on androgens. [P3] These biochemical brain differences, apparent from age four, determine behaviour, sexual orientation, and gender identity. [C] Therefore, because there are biochemical differences in the brains of men and women determining behaviour, gender is not a social construct.

Counter-arguments

It is averred that the differences in the brain are negligible as there are no significant differences based on sex alone. This distinction between the male and female brain seems to suggest that all males think and operate on one level and all females think and operate on another. There are variations and differences in thinking, aptitudes and personalities, which need to be considered. The biological distinction between a male and female can actually be harmful as it suggests that one gender may not have the aptitude for something that the other has, when that is simply not the case.

Rejecting the premises

[Rejecting P1] Prenatal androgen exposure influences how some brain structures develop, but the premise slides from influence to determination — and "develops as a male or female brain" treats a set of overlapping continuous measurements as two discrete kinds. [Rejecting P2] Group averages do not describe individuals: the reported differences are means with wide overlapping distributions, so a person's sex does not predict their measurements, and the structure named regulates particular functions rather than behaviour in general. [Rejecting P3] The strongest claim is the least supported. No established finding shows these structures determining gender identity or sexual orientation, and even a wholly biological account of a trait would not settle whether the social expectations attached to it are constructed — which is what the question asks.